The invention relates to a mast footing for a windsurfing rig having a force reduction device in order to, tension the leading edge of the sail.
A mast footing of this type is disclosed in German Patent DE 3,633,752 C2. There, in order to tension the leading edge, a tensioning device is used which has a rod and a silent ratchet, adjustable in steps, which may be operated by means of a hand lever. The rod and the silent ratchet are arranged in the interior of a tubular mast footing which features a longitudinal slot, which is penetrated by the hand lever. The force required in order to tension the leading edge may be applied effortlessly with the tensioning device. However, the tensioning device for the leading edge has, on the whole, a relatively great weight, which does not achieve weight-saving goals. Today, great efforts are being made to save weight in the area of the rig.
With modern rigs and sails, an optimal tension of the leading edge and the bending of the mast connected therewith is determined, in essence, by means of the cut of the sail and should vary over, at most, only a very limited range in response to the strength of the prevailing wind. Consequently, the range of fine-tuning amounts to only a few centimeters. In this connection, the force which must be applied to the leading edge for an ideal bending curve of the mast lies between 200 kp (1962 N) and 400 kp (3924 N). Yet, most windsurfers fear a mast break, such that in practice, the leading edge is not tensioned adequately and, consequently, windsurfing is undertaken without the sail being optimally trimmed.
Tensioners for the leading edge used by most surfers today consist of a tackle which is reeved fourfold to sixfold, one end of which has a hook which is secured in a loop of the sail and the other end of which is fastened to the mast footing. In addition, a sheet clamp is present at the mast footing, in which the free end of the line of the tackle is loaded. With this stretcher for the leading edge, the problem also occurs that the tensile force required in order optimally to trim the sail can scarcely be applied by one person and that the end of the tackle, part of which is quite long, must be stowed after tensioning, which is commonly carried out by means of winding it about the mast footing or stowing it inside the mast footing.